Ok I have bought 3-rd party iPod chargers of eBay (as I am in EU and my iP had a USA wall charger in the box) and I am using them with the iPhone. I have noticed the following though, while using the wall charger:

Although it charges the iPhone from empty to full in about 2.5 hours, the screen is more or less disabled while plugged in. I can see the "slide to unlock" but I cannot slide it (I try but it does not respond)! The strange thing is that is charges properly, and fully, so no problem with that, but I just cannot use the phone while charging. If I unplug it, it goes back to normal, everything is ok.

This does not happen if I simply use the usb cable and charge it from my laptop, but I do not have my laptop withme all the time.

Anyone else experiencing this? Any suggestions? could it be that my charger is UK 3-pin so I also have to use an adaptor to change it to 2-pin EU-Greek style fuse?